A salary cap squeeze and new contracting protocols will result in Wallabies back-rower Scott Higginbotham leaving Super Rugby champions Queensland next season for a richer two-year deal with the Melbourne Rebels.

Almost a month after agreeing with the Reds to stay at Ballymore, the Rebels on Friday officially confirmed the raw-boned 11-Test flanker would play for Melbourne in 2013 and 2014.

Higginbotham's change of plans came after the Australian Rugby Union's (ARU) top-up offer to the in-form forward fell short of what he and Queensland officials expected.

Before this year, players negotiated with the ARU first for top-up deals before deciding on their province.

With Welsh No 8 Gareth Delve leaving Melbourne at the end of the year, the improving Rebels successfully lured the athletic 25-year-old south in a huge boost to the fledgling franchise.

Higginbotham is rated Australia's best blind-side flanker and is set to beat Rocky Elsom to the Wallabies No 6 jersey for next month's Tests against Wales and Scotland.

It's only the second time since Ewen McKenzie became Queensland coach that the Reds have lost a starting player they wanted to keep after the Rebels also lured prop Laurie Weeks in 2010.

A disappointed McKenzie felt the ARU's new contracting process, which is set to include a yet-to-be-determined salary cap, let a frustrated Higginbotham down after he wanted to stay in Brisbane.

''We have to work within our structures,'' he told AAP.

''We offered him a good deal and we've delivered a good rugby program to him that's made him a Wallaby and that's all you can do.

''At the end of the day, he'd like to be living in Queensland and surfing the beaches up here.

''But the bottom line is we can only pay players what they are individually worth in our squad.''

The retention of vice-captain Will Genia and continued efforts to keep fellow Wallabies star Quade Cooper have ensured an even tighter budget to work with for the defending champions.

After snaring Kurtley Beale and James O'Connor for the 2012 campaign, Rebels coach Damien Hill said Higginbotham would also quickly add to the new club's skill and culture in 2013.

''We believe Scott is a player whose best football is in front of him. He is without doubt a player on the rise,'' Hill said.

Meantime, Hill named an unchanged starting 15 from that which upset the Crusaders 28-19 for Sunday's clash with the Western Force in Perth.